1. Field of the Invention
The present invention relates to transcutaneous medical devices and to a process for their production.
Transcutaneous medical devices are implants such as, for example, indwelling catheters which pass through the skin and remain in the body for a lengthy period.
2. Description of the Background
Examples of transcutaneous implants include catheters for peritoneal dialysis and catheters for long-term perfusion therapies. However, on long-term use of these and other implants, there is a risk of infection by bacteria or other microorganisms entering the body, which intrusion results from various movements of the body which exert transient tensile and compressive forces on the passages by which the implants pass through the skin. Fissures periodically form at the interface between the passages through the skin and the skin tissue, through which microorganisms can enter and infect the body.
Several proposals for the fixation of transcutaneous implants in the skin have been made in order to prevent infections. For example, transcutaneous devices such as catheters for peritoneal dialysis using cuffs are disclosed in the literature for such a purpose.
Cuffs are hollow cylinders which are a few mm to a few cm long, which surround the catheter. The cuffs are placed on the catheter, singly or multiply, by pulling on or by sticking on an appropriate tape. The task of the cuff is to come into close contact with body tissue by way of its outer surface thereby fixing the catheter and preventing microorganisms from migrating into the body at the catheter/body tissue interface. To achieve this objective, the outside of the cuff consists of Dacron (see U.S. Pat. No. 5,057,075), which is a material regarded as compatible with the body or of a porous material (see U.S. Pat. Nos. 5,308,338 and 5,141,499), into which body cells can grow.
As an additional measure to prevent microbial infections entering the body through the passage through the skin, cuffs are occasionally employed in combination with antiseptic substances. U.S. Pat. No. 5,308,338 discloses a tube which passes inside the catheter and through which antiseptic liquids can be delivered to the cuff material.
U.S. Pat. No. 5,049,140 describes the use of antimicrobial substances in the cuff material.
A number of patents which disclose a fixation and/or prevention of infection in connection with the use of transcutaneous catheters include U.S. Pat. Nos. 5,098,413; 5,057,075; 4,772,269; 4,687,471 and 4,623,329. The patents describe catheters of particular geometric embodiments for individual types of use.
Although the use of cuffs in the prior art can extend the period of use of the catheter, after which the catheter must be changed because of signs of infection, the problems of fixation and prevention of infection when the transcutaneous devices are used over a long period use have not yet been satisfactorily solved. In particular, the ingrowth of body tissue into porous materials does not result in a durable connection which reliably prevents the penetration of infectious organisms into the body. The use of antimicrobial and/or antiseptic substances in this connection is to be regarded as a temporary measure which is susceptible to failure and difficult to implement.
Collagen-containing composite materials are known from a different technical area to be materials which readily form adhesions to the human body (German Patent No. 36 327 316, German Application No. 195 29 036.4). A need continues to exist for a way in which to prevent infection in the use of transcutaneous devices in the human body.